Submarine tanker for transportation of liquid cargo

ABSTRACT

In the transportation of liquid cargo either by submarine or surface vessels, compartmentalized storage cells defining a structural part of the vessel are each made up of an outer tank or chamber enclosing an inner expansible bladder in which the liquid cargo is stored and isolated from the rest of the chamber. Inlets at the lower end of the chamber permit entry of water into the lower portion of the chamber, and upper inlets in the upper portion of the chamber permit introduction and removal of air or other gas into and from each chamber respectively either to regulate the buoyancy of the vessel, to permit removal of undesirable gases, or to fill the space occupied by the bladder during unloading of the cargo. The buoyancy of the cargo chambers or of separate buoyancy chambers within different sections of the vessel can be regulated independently or simultaneously to selectively vary the trim or ballast of the vessel.

United States Patent [191 Hamilton Dec. 2, 1975 [76] Inventor: Ferris F. Hamilton, 320 High St.,

Denver, Colo. 80218 [22] Filed: Oct. 14, 1971 [21] Appl. No.: 189,302

Related US. Application Data [63] Continuation-impart of Ser. No. 3,307, Jan. I6,

1970, abandoned.

[52] US. Cl. 114/74 R; 114/16 R [51] Int. Cl B63b 25/08 [58] Field of Search 114/74 A, 16 R, 74 R,,69,

114/65 A, 72, 74 T, .5 T; 220/63 R, 63 A [56] References Cited UNITED STATES PATENTS 6/1911 Peebles 2/1957 Norway ll4/74 R 6/1950 Canada 114/74 T Primary Examiner-George E. A. Halvosa Assistant Examiner--Stuart M. Goldstein [57] ABSTRACT In the transportation of liquid cargo either by submarine or surface vessels, compartmentalized storage cells defining a structural part of the vessel are each made up of an outer tank or chamber enclosing an inner expansible bladder in which the liquid cargo is stored and isolated from the rest of the chamber. Inlets at the lower end of the chamber permit entry of water into the lower portion of the chamber, and upper inlets in the upper portion of the chamber permit introduction and removal of air or other gas into and from each chamber respectively either to regulate 1,302,547 /1919 Heidenreich ll4/74 R the buoyancy of the vessel, to permit removal of undel,953,389 4/1934 Bolton et a ll4/7 R sirable gases, or tofill the space occupied by the blad- Hal'rls R de during unloading of the cargo The buoyancy of 2394-607 2/1946 Gray et 4/74 R the cargo chambers or of separate buoyancy chambers 2 2222 3 2551 E within different sections of the vessel can be regulated 313561251 12/1967 Roberts 220/63 lgg g i g g g to selecmely Vary FOREIGN PATENTS OR APPLICATIONS 2,052,113 3/1971 Germany 114/74 R 23 Claims, 15 Drawing Figures i .../j i 23 23 2 23 23 4o 43 42 40 40 4o 42 P p 1 142 L 40 44 4| US. Patent Dec.2, 1975 Sheet 1of6 I 3,922,985

I INVENTOR FERR/S F HAMILTON ATTORNEYS US Patent Dec. 2, 1975 Sheet 2 of6 3,922,985 I US. Patent Dec. 2, 1975 Sheet4 of6 v 3,922,985

US. Patent Dec. 2, 1975 Sheet6of6 3,922,985

SUBMARINE TANKER FOR -TRANSPORTATION F LIQUID CARGO This application is a continuation-in-pa'rt of my application, Ser. No. 3,307, filed Jan. I6, I970 now abandoned.

This invention relates to novel and improved means for the commercial transportation of liquid cargo, such as, for instance, oil and other petroleum products; and more particularly relates to transportation of such cargo either by surface ships or submarines in a safe, economical and dependable manner."

Water transportation of oil and other petroleum products present special problems and difficulties inso-.

far as safe handling, storage 'afnd efficient transportation are concerned, particularly in long distance transportation in which the liquids will tend to undergo ex pansion and contraction. In the transportation of liquid cargoof the type described, whether by boat or submarine, special care must be taken to regulate the buoyancy of the vessel and at the same time prevent undesirable contamination as well as comingling of the oil with fluids or liquids employed to regulate the trim and ballast of the vessel. Moreover, the means provided for storing the liquid cargo desirably should facilitate safe; rapid handling of the cargo in filling and removal from the container and maintain complete separation of the cargo from the sea water and fluids in order to prevent loss of residue or possible contamination.

Water transportation of petroleum products recovered in far northern or Arctic regions of the world presents unique requirements: Many of the waterpassags and straits are impassable because of great ice accumulations and necessitate underwater transportation over i at least a part of the distance. Accordingly, the buoyancy of the vessel must be adjustable over a wide range to permit travel underwater andbeneath such ice accumulations with or without cargo and requires not only close control of the overall buoyancy of the vessel but selective variation in the buoyancy or trim in different sections of the vessel. I A

It is therefore a desirable object and feature of the present invention to provide for novel and" improved storage cells adapted for transportation of liquid cargo in submarine or surface transport ships, and which in modified forms will facilitate e'ithertop orbottom loading into the storage cells.

It is another object of the present invention to provide for a novel and improved method and means for transportation of liquid cargo in a network of individualized compartments or cells which may serve as" combination storage cells and ballast tanks arranged in uniformly distributed, mutually reinforcing relation within the vessel; and further wherein the flexible expandable means are suspended and sealed within each cell to contain and isolate the cargo from the rest of the cell and which means can be selectively removed for periodic cleaning in a rapid, simplified manner without damaging the rest of the cells. I

It is a further o'bject'to provide fora honeycomb network of storage cells occupying a partor allof the vessel which are low-cost in constructionipre ssure andfirnpact-resistant and form a structural partof the vessel. Additionally, the storage cellsmay include a combination of central chambers occupied solely by oil cargo and outer, vertically disposed chambers having expansible bladders for containing the cargo and'is'o lating the same from the remainder of the cell.

It is a still furtherobject ofthis invention to provide in a submarine tanker or surface ship for a combined ballast/oil cargo storage cell which affords maximum safety" and handling in transportation of the oil and compensates for expansion or contraction of the oil in transit without the danger of comingling or contamination of the s'ea' water, the cargo in each cell being isolated from the ballast as well as from the other cells to minimize lossin cargo or ballast in the event of damage or loss of cargo in anyone cell or section of the vessel.

In accordance with the present invention,'tr ansportation of liquid cargo, such as, for instance, oil or other petroleum products, in a submarine or surface ship is greatly facilitated by the utilizationof compartmentalized storage cells which are uniformly distributed throughout a 'major portion of the vessel and are so constructed and arranged as to define a structural part of the vessel. At least certain of the storage cells are comprised of outer, heavy-walled .or pressure-resistant tanks vertically disposed in side-by-side relation and each containing an inner expansible bladder in which the liquid cargo is stored and isolated from the rest of the tank and from the cargo in other cells. The tank may be either partially or entirely filled with ballast in surrounding relation to the bladder, preferably 'by introdu'ction of sea water through the lower end of the tank together with the controlled introduction of air or other gaseous fluid into the upper end of the tank in order to regulate the resultant buoyancy of the tank. By regulating the buoyancy of one or more selected cells, the buoyancy and trim of the entire vessel can be closely regulated and controlled without the necessity of utilizing special ballastltanks. Moreover, the expansible bladder or container serves to isolate the liquid cargo from the ballast and other fluid in the tank and provide a safe means of transportation of the cargo. In alternate forms of the present invention, each bladder is sized to occupy substantially the entire cell when filled with oiljand when the oil is removed the space in the cell can be replaced by sea water' in surrounding relation to the bladder; also, central chambers may be provided solely for the storage of oil. Convenient access tubes are provided for the oil supply system as well as for seawater, gas and oil distribution into and from the outerand central cells and chambers.

The foregoing and otherobjects, advantages and features of the present invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings, in which:

FIG. 1 is an overall plan view schematically illustrating a submarine tanker in accordance with the present of the submarine tanker FIG; 5 is an enlarged sectional view of one of the storage cells in ac'cordance'with the present invention.

' FIG. 6 is ane'nlarged cross-sectional view of the storage cellshown in FIG. 5.

FIG. 7 is a view schematically illustrating th'econtrol circuitfor regulating the introduction and removal of oil and gas into 'and from each of the storage cells.

FIG. 8 is a top plan view of an alternate form of submarine tanker in accordance with the present invention.

FIG. 9 is an elevational view of the form shown in FIG. 8.

FIG. 10 is a view in more detail showing the cargo section of the vessel shown in FIGS. 8 and 9.

FIG. 11 is an enlarged cross-sectional view of the cargo section taken about lines l1ll of FIG. 10.

FIG. 12 is a cross-sectional view in more detail showing the details of a single cell structure of a wing tank cargo section.

FIG. 13 is a somewhat schematic diagram of a cargo loading and unloading circuit for the form of tanker shown in FIGS. 8 to 12.

FIG. 14 is an enlarged cross-section view of a modified form of bottom-loading wing tank in the cargo section for a vessel of the type shown in FIGS. 8 to 10; and

FIG. 15 is a cross-sectional view in more detail of a single cell structure in the bottom-loading arrangement shown in FIG. 14.

Referring now to the drawings, there is shown by way of illustrative example in FIGS. 1 and 2 a cargo-carrying submarine 10 having a main outer body or shell 12 with an upper deck 13, and thrust engines 14 are provided with propellers 15 at each end of the body in order to provide complete reversibility of the submarine as well as redundancy in its operation. For the purpose of illustration and not limitation, the submarine has a generally rectangular body form with tapered ends 16 at its stem and stern, and the vessel is conventionally equipped with the usual crew quarters, pressure hulls, machinery and power plant space, not shown, but which are generally concentrated at the opposite tapered ends 16 of the submarine. Steering planes or faired-in rudders 17 are shown along the external surfaces of the body directly behind each of the thrust engines to provide additional directional stability and guidance for the submarine. While thrust engines have been illustrated, various conventional types of propulsion systems may be utilized in accordance with the conventional practice in the submarine described and which is intended more as a setting for the principal and important features of the present invention.

Referring to FIGS. 3 to 6, the major portion of the submarine, and specifically that section 18 between the tapered end portions 16, is defined by a series of vertically disposed storage cells 20 which are specifically adapted for carrying liquid cargo, such as, oil or other petroleum products. As illustrated in FIGS. 3 and 4, the external casing of each of the cells is in the form of a generally rectangular tank or chamber 22, and the cells are rigidly interconnected in honeycomb fashion; such as, by welding or otherwise fastening them together throughout the length and breadth of the section 18.

In each cell, the outer rectangular tank 22 is comprised of side walls 23, a top closure panel 24 and a bottom closure panel 25 closing the upper and lower ends, respectively, of the tank. An inner, expansible bladder 26 composed of a reinforced rubber or rubberlike material not reactive to the cargo to be carried is enclosed within the shell to contain the cargo. As best seen from FIGS. 5 and 6, the bladder is generally circular in crosssection and elongated with a downwardly convergent, lower end 28 being closed and anchored by a pin 29 to a clevis 30 on the bottom end surface 25 of the tank. If desired, the bladder may also be fastened at selected points 32 to the inner side wall surfaces of the tank but 4 with the intervening portions of the bladder between the fastening points being free to expand or contract, for example, as shown in FIG. 6, by forming longitudinal folds or pleats lengthwise of the bladder. The upper end of the bladder is provided with a circular inlet 35 which receives an inlet pipe 36 extending downwardly through a central opening 37 in the top 24 of the tank, the pipe 36 extending into each cell from a main header or manifold system to be described and including a main supply pipe 38, there being a valve 39 in each inlet pipe 36 which is normally closed to isolate the cargo in each cell from that of the other cells and is opened only for the purpose of loading and unloading.

As stated, the cells are vertically disposed within the submarine and traverse substantially the entire depth of the submarine with the walls 23' of the outer cells preferably serving as the external skin or hull of the submarine. For this purpose, the outer walls 23 are given an added thickness for increased pressure and impact resistance, while the walls 23 of. the inner cells may be of reduced thickness, since the cells are arranged in mutually reinforcing relation and much of the pressure resistance needed is supplied by the outercells. Preferably, the cells are dimensioned to be of a length corresponding to the depth of the submarine with the upper ends of the cells being disposed beneath the upper deck 13 of the submarine and the lower ends terminating directly above the undersurface or skin of the submarine. In order to serve as variable ballast tanks, the bottom panel of each cell is provided with sea water inlets 40 and outlets 41, each of the inlets and outlets 40 and 41 including a pilot-operated or remote-controlled valve 42 in order to regulate the amount of sea water introduced and removed, respectively, from each cell. Preferably, sea water is delivered through a central supply pipe 40, leading into each of a series of a lines 40 by a pump represented at 43. In turn, the sea water is removed through an exhaust pipe line 41' including a pump represented at 44.

The top panel of each cell is in turn provided with an air inlet line 45 including a pilot-operated or remote control valve 46 for the controlled introduction of air or other gaseous fluid under pressure into the upper end of each cell. An air exhaust line 48 including a pilot-operated or remote control valve 49 for each cell is provided for the controlled exhaust or removal of the air or other fluid from each cell.

In each cell or series of cells, the buoyancy may be closely regulated by regulating both the amount of sea water introduced into the cell and the density or pressure of the air or other gaseous fluid introduced. Preferably, the buoyancy of each cell may be independently regulated; or a group of cells in a particular section of the vessel may be regulated independently of the other cells; or all of the cells may be simultaneously regulated through a central control panel equipped with control switches for the sea water valves 42 as well as the air inlet and exhaust valves 46 and 49. Thus, it is possible to regulate not only the total effective buoyancy of the vessel but its forward and aft trim as well as the auxiliary trim whether on the surface of the water or in a submerged condition.

There is schematically shown in FIG. 7 a high pressure system for selectively introducing and venting air or gas from each of the cells in the vessel. Air inlet lines 50 are arranged in parallel to supply the rows and columns of cells from a common source of air under pressure 52. The air inlet valves are represented at 46 and as stated are under remote control in a conventional manner to selectively determine their open or closed condition.

Similarly, air exhaust lines 54 are arranged in parallel from the opposite ends of the vessel into exhaust or vent lines for the air or gas through a common outlet 55, and again the outlet valves 49 are remotely controlled to selectively exhaust the air or gas from one or more of the cells.

The network described with respect to introduction and removal of air and gas from each of the cells would similarly apply to the introduction and removal of sea water into and from each of the cells with the pipe lines running beneath the cells in parallel and provided with a pumping system for the inlet and outlet lines to selectively pump sea water into or away from one or more cells.

It will be apparent that it may not be necessary to equip all of the storage cells with valved jinlet and outlet ports, and that certain of the cells may'have inlet and outlet ports in open communication with the sea water so that the sea water will seek its own level in the cells. For example, in FIG. 5 as illustrated, the bottom panel 25 is merely provided with openings 60 to permit free passage of the sea water into and out of the cells. In certain applications, for example, surface vessels, it may be possible to dispense entirely with the valved air and sea water supply and removal system and to regulate or vary the buoyancy of the vessel through independent means, since the cells will serve as an effective means of containing the liquid cargo while structurally reinforcing the vessel.

Moreover, it will be evident that other gaseous fluids may be used in place of air to regulate the buoyancy of the cell. For example, in submarines utilizing hydrogen peroxide as a fuel and as a source of oxygen, the exhaust may also serve effectively in place of air by controlling its delivery and removal into and from each cell.

In the preferred form, the oil or other liquid cargo is piped into each of the individual cells through a common inlet line 62 communicating with the pipe lines 38 directed along each column of cells. Again, filling of each bladder may be individually controlled by the valves 39 in the inlet pipes 36 leading to each bladder and either may be manually controlled at the inlet or remotely controlled through a central control panel. The oil supply system as described and represented may also serve for removal of the oil from each of the bladders by selectively opening each of the valves and withdrawing the oil through the lines 38 into the main line 62. In transit, the valves 38 are closed so as to isolate the liquid cargo in each cell. In this way, should individual cells be damaged or suffer loss of cargo, it will not affect the cargo in the other cells.

By storing the liquid cargo in individual compartments or cells vertically disposed in a honeycomb arrangement throughout the vessel closer control over the total buoyancy of the vessel is achieved requiring a minimum of equipment. The individualized, vertical cells will minimize inertial effects of the liquid cargo in pitching or tipping of the vessel in a particular direction, and the individual expansible bladders will also minimize the effects of thermal expansion and contraction while isolating the cargo from the sea water ballast and fluid in each cell. This is of particular importance in transportation of oil and other petroleum products where it is essential to prevent comingling or possible contimaination resulting from the loss of residue from the cargo containers. Of course, the size and strength of these cells will be dictated largely by the conditions of use and whether they are to be utilized with or without other means of controlling the effective volume and weight displacement of the vessel in water. In this connection, the cells may be arranged to occupy the entire space throughout the major section of the vessel as described or be placed only within selected sections of the vessel such as fore and aft and along the port and starboard sides.

While each cell in the form shown in FIGS. 1 to 7 has been described as having an outer rectangular tank, the tank may assume various configurations, such as, another polygonal form or cylindrical form, and the bladder may either conform in contour to that of the tank or be of a different cross-sectional configuration as described so as to permit the free movement of sea water into the tank and into surrounding relation to the bladder. Of course, if the bladder is designed to conform to the cross-sectional configuration of the tank it may be desirable to provide bypass lines for passage of the sea water from the lower into the upper portion of the tank. Thus, to provide added pressure-resistance, the outer cells may be cylindrical in cross-section or the entire network of cells may be cylindrical.

In the alternate form of invention shown in FIGS. 8 to 12, a submarine tanker 66 is made up of an outer stream-lined shell 68 provided with an upper deck 69, and the shell 68 is of elongated stream-line configuration provided with convergent ends 70 and 71 at its stem and stem, a prow 72 at the front tapered end and an ice-breaking sail 74 on the upper deck surface 69. A suitable means of propulsion is provided including a propeller represented at 75 at the rear tapered end. The vessel again is equipped with the usual crew quarters, pressure hulls, machinery and power plant space which as described in connection with the form of FIGS. 1 to 7 are generally concentrated at opposite tapered ends of the submarine, and a cargo section generally designated at'76 extends through the intermediate portion of the submarine and is broadly illustrated in FIG. 10. As best seen from FIGS. 10 to 12, longitudinal bulk heads 78 and transverse bulk heads 79 together with intermediate transverse bulk heads 80 serve to divide the cargo section of the tanker into separate compartments consisting of the central, longitudinally extending compartments 81 and outer wing tanks or cells 82. The body of the submarine tanker is preferably composed of a high-strength, reinforced concrete which is cast in sections or otherwise formed, as particularly illustrated in FIG. 11, into a relatively wide, flat rectangular configuration which is recessed to define circular openingsfor the central cargo compartments 81 and generally rectangular or cubical openings for the tanks 82 flanking opposite sides of the central compartments 81. The external surface of the concrete body or shell is covered with an outer skin or metallic lining 84 along the upper deck 69 as well as the vertical sides 85 and flat bottom 86 of the vessel. As shown, the center section is divided into longitudinally extending compartments 81 disposed in end-to-end relation to one another by the transverse bulkhead 80, and each center compartment is of elongated generally circular configuration and provided with an air-tight metallic liner 88 covering the inner circular wall surface as well as the ends of each compartment at the bulkheads. Depending upon the size of the vessel, a single continuous 7 compartment 81 may be formed with the bulkheads positioned only at opposite external ends or centrally divided as shown.

In turn, a series of four or more cubical wing tanks are formed along opposite sides of the vessel by the outer transverse bulkheads 80, each wing tank 82 having a relatively thin-walled liner 89 covering the wall surfaces to form an air-tight, pressure-resistant compartment, and an enlarged central opening 90 projects upwardly from the top of each tank 82 through the body of the vessel to the deck surface. A mandrel assembly is inserted downwardly through the upper central opening for suspension within each wing tank, each mandrel assembly consisting of a flexible, expansible container in the form of a bladder 92 mounted on a central mandrel 93. The mandrel 93 is of generally tubular construction and provided with a series of spaced openings 91 which define ports for delivery and removal of liquid cargo into the bladder, and the mandrel is dimensioned to extend the whole depth of the cell with its closed lower end 95 either resting on or terminating slightly above the bottom surface of each wing tank. As seen from FIG. 12, an attaching flange 96 is connected to the lower end 95 with aligned annular grooves therebetween to receive the circular beaded edge 98 formed at the bottom end of the bladder 92. Connecting bolts 99 serve to clamp the bottom attaching flange 96 firmly against the underside of the bladder to secure the bladder in place at the lowerend and to form a sealed connection therebetween.

In the alternate form, the bladder is again preferably composed of a reinforced rubber or rubber-like material which is non-reactive to the cargo and which is capable of expansion from a collapsed condition along the external surface of the mandrel to a fully expanded position occupying the entire space within the wing tank, as illustrated in FIG. 11. The upper end of the bladder also is provided with a beaded circular edge 100 which is clamped between upper and lower attaching flanges 101 and 102, each of the flanges being of annular configuration and disposed in surrounding relation to the upper tubular end 104 of the mandrel tube and interconnected by bolts 105 as illustrated. Suitable seals 106 are positioned in grooves on the internal surface of the upper attaching flange 101 for sealed engagement with the external surface of the upper end 104 of the mandrel tube and the entire assembly is held in place within a counterbore formed at the lower end of the mandrel head 107 by locking screws 108. The upper extremity of the upper end 104 is suitably threaded to make up with an internally threaded coun-. terbore 110 directly above the counterbore in which the upper attaching flange 101 is seated. In connected relation it will be noted that the upper end 104 of the mandrel tube forms a continuation of a central opening 112 extending vertically through the mandrel head and the opening is threaded at its upper end to receive a lifting eye 113. Additional internal threading may be provided adjacent to the part 118 for a suitable blanking plug, not shown, but which is threaded onto the opening 112 and serves to close off the central opening 112 to the mandrel for the purpose of testing the O-ring seals 116.

The mandrel head 107 is of generally cylindrical configuration with an enlarged upper rim 114. Axially spaced, annular grooves 115 on its external surface receive suitable O-ring seals 116 above and below a central groove 117 which communicates with a lateral supthe mandrel head for communication with the central opening 112. It will also be seen that the mandrel head 107 is seated in flush relation to an outer support ring 120, the outer support ring being complementary to the external surface of the mandrel head with an upper rim portion 122 forming flush continuation of the rim 114 along the upper deck surface of the vessel. Thus the mandrel head is preferably given a length sufficient to extend through the full thickness or depth of the upper shell or body portion of the vessel beneath the deck surface and with the upper rim portions being disposed in flush relation with the upper deck surface of the vessel. In this relation, the outer ring member is attached permanently in place to the body of the vessel, and the mandrel head is made to be readily attachable and detachable to and from the outer ring by the hatch bolts 124.

In the loading and discharging of-oil into and from each of the wing tanks, fuel supply and discharge lines 125 extend horizontally through the upper body portion of the vessel from the upper access tubes 126 or 127 in the upper central part of the vessel into alignment with the center groove 117 on the mandrel head. In the access tubes, the lines are connected into the headers 128 positioned on opposite sides of the central compartments 81 in separate access tubes located directly beneath the main access tubes 126 and 127. Thus oil is supplied to the main headers 128 and may be controlled for delivery into each of the lines by suitable valves 129 in the upper access tubes 126 and 127 for regulated flow through the laterally extending lines 125 and ports 118 as well as the central openings 112 through the mandrel tube 93 to fill up each bladder 92. The same series of lines serve as discharge means for removal of the oil into the headers 128 by means of an unloading circuit to be described. It should be pointed out however that the main headers 128 extend the entire length of the cargo sections and, beyond the cargo sections, are made accessible through the external surface of the vessel for make-up or connection into an off-shore terminal. Lower access tubes 131 and 132 are positioned on opposite sides of the central compartment in the lower end of the body of the vessel and extend the full length of the cargo section, the access tube 131 housing headers having suitable valves 130, shown in FIG. 13, to selectively control the introduction and removal of sea water into and from each of the wing tanks, and the valves 130' preferably are automatic/manual pressure relief valves which will equalize the water pressure between the insides and outsides of the tanks, especially under rapidly changing pressure conditions. Here an inlet port 133 having a filter represented at 134 is in communication with the headers 130 and branch lines 135 extend away from the headers 130 into communication with the lower ends of each of the wing tanks. The access tube 132 in turn may serve as a suitable housing for other electrical equipment and conduits used in the operation of the vessel and has an air vent 136 in communication therewith. Another air vent 137 located above the access tube 132 serves as a source of return air for the upper access tubes 126 and 127. The upper access tubes 126 and 127 each contain air lines 138 which communicate with air vents 139 leading from the wing tanks in order to permit introduction and removal of air into and from each of the outer tanks. Also, gas vents 140 are positioned in the upper tubes 126 and 127 having connecting lines as shown into the oil supply and discharge lines 125, as well as a separate gas vent line 141 which communicates with the upper end of each of the center compartments 81. In the alternative, the gas vents 140 may communicate directly with the center opening 112 through a separate line for removal or venting of gas from each tank. 1

A separate center compartment process tube 142 is positioned in the lower end of the central compartment and contains an oil header system 143 with an oil line 144 for supply and discharge of oil into the central compartment. The center process tube 142 as well as the outer tubes 126-127 and 131-132 are of sufficient size to permit ready access by repair or maintenance men to the header, valve, vent, and equipment systems located in the tubes, each of the man-ways or tubes being accessible from one or both ends of the cargo section of the vessel. Briefly summarizing, the air vents 138 are provided for each cell as well as the central compartments to aid in filling the space as the oil is removed from the bladders or membranes 92, whereby the bladders are contracted into a collapsed condition around the mandrels; also they permit escape of air in order to prevent undue pressure build-up in any of the cells or compartments. Similarly, the gas vents 140 permit gases entrained in the oil during loading to escape and be removed from each tank. As hereinbefore described, sea water may be introduced selectively into the outer wing tanks. This is of particular importance after the oil has been unloaded in order to act as ballast for the vessel on its return trip in an unloaded condition. In the removal of crude oil, the perforated mandrel tubes 94 encourage complete removal of the oil as well as sediment and residue which may otherwise collect in the lower end of the bladder, and for this pur pose may also be fluted or striated on its external surface to permit complete removal of the'oil. Moreover. by spacing openings or ports throughout the substantial length of the mandrel tubes, should the lower ports be closed by collapsing of the bladder, the upper ports will continue to remove the oil or other liquid cargo until completely empty.

A particular problem associated with the handling and shipment of oil and other petroleum products is the collection of residue; and while the fluted mandrel construction will minimize build-up of sediment and residue in the bladders it is necessary at periodic intervals to clean out or flush the bladders. In accordance with the present invention, convenientand ready means of attachment and removal of the mandrel assembly is provided so that at desired intervals, once the oil cargo is unloaded from each bladder, the mandrel head may be detached and the entire mandrel assembly removed from the tank. The bladder is then removed from the mandrel tube to permit complete cleaning of the insidev of the bladder. For the reason that the center compartments are intended to serve solely as oil cargo compart- As illustrated in FIG. 13, a typical form of loading and unloading circuit is shown which is adaptable for use with the alternate form of invention shown in FIGS. 8 to 12. Supply hoses having control valves l60 are connected into a series of four parallel lines 152, 153, 154 and 155 which in turn are connected to line 156 from surge tank 157, line 143 which is connected to the 10 oil line 144 for thecenter compartments, oil headers 128 on the port and starboard sides of the vessel for supplying oil into the outer wing tanks. For the purpose of clarity, those valves designated 160 are open during the loading cycle and closed in the unloading cycle;

those designated 161 are closed during the loading cycle and opened in unloading; and still other valves 162 remain open both for loading and unloading. In each case the control valves can be adjusted to regulate the flow capacity of oil into and from the vessel.

When loading, oil is directed through the lines 143 and 128 to the central compartments and wing tanks, and one line 128 is illustrated in more detail as being connected to the branch supply lines 125 into the top of each of the wing tanks, each line 125 including a control valve 164 and meter 165 in order to regulate the relative amounts of oil supplied to each wing cell. Suitable liquid volume controls 178 are positioned in each cell to sense and indicate the oil level. Hydrocarbon sensing devices, not shown, may also be positioned in each of the wing tanks outside the cargo bladder to sense the presence, if any, of hydrocarbons in the sea water surrounding the bladder and, if detected, sound an alarm indicating a leak in the bladder. As illustrated in FIGS. 11 and 12, the lines 125 are also joined with the gas vent lines 126 which lead into a high volume drip pot or separator 166, and each of the lines 126 is provided with a normally closed valve 167 which is opened as required in transit and in unloading oil to remove and vent the gases which collect within each of the wing tanks. These gases are separated from the oil in the separator 166, and a pump 168 will pump any oil collected through the surge tank 157 and through line 156 either to the unloading lines designated at 170 or through the lines 128 and 143 back into the tanks and compartments. Similarly, oil is unloaded through the lines 128 and 143 by the unloading pumps 172 in each of the lines 153 and 155 for removal through the unloading line 170. The sea water lines are represented at 135 and the inlet/outlet port represented at 133 for introduction and removal of sea water through the bottom of each wing tank, each line 135 having a separate valve 130' and meter 130". An additional valve 130' may be positioned on the opposite side of each meter 130", and the valve 164 may be positioned on the other side of each meter 165 from the valve 164 illustrated in each of the lines 125. The separate air vent lines are represented at 138 and lead into the upper ends of the wing tanks, and each has a pressure relief valve 138'.

From the high volume separator, a liquid level control regulates the working of 'the pump 168 when necessary to remove oil separated from the gases, and the gases are'passed through molecular seal 182 to remove anyremaining liquids. The gas is then removed, such as, by flaring through a separate stack as illustrated. Although not shown, in the event that a tank or compartment overflows a high liquid level control in parallel with control 180 will activate a high volume pump disposed in parallel with pump 168.

In another form of the present invention, as shown in FIGS. 14 and 15, the cargo vessel is basically of the same construction and arrangement as shown in the form of invention illustrated in FIGS. 8 to 12 and accordingly like parts are correspondingly enumerated;

however, it will be noted that the oil header 128' communicates'with the oil supply and discharge lines 125' through the lower access tube 132 for supply and dis- 1 1 charge of oil through the lower ends of the wing tanks into communication with the lower ends of the mandrel tubes 93. In this way, cavitation and surging of the oil during the unloading cycle is minimized, although it does require connection through the lower ends of the mandrel tubes. For this purpose, in the modified forms of mandrel tubes as shown in FIG. 15, the lower end of the tube is left open and is provided with a tubular extension 190 on the bottom attaching flange 96 which is inserted in a circular recess 188 in the bottom of the wing tank, and the tubular extension is provided with O-ring seals 191 engaging the inner wall of the recess 188 and a lower inturned edge 192 which abuts the upper end of the oil supply and discharge line 125. In addition, an enlarged annular seal 194 is positioned in surrounding relation to the upper end of the tubular extension and is flared outwardly as at 195 to form a sealing skirt against the undersurface of the bladder and is also flared downwardly as at 196 along the external surface of the tubular extension. The oil line 125' has an elbow-shaped riser portion 197 which abuts the lower end 192 of the extension, and the oil lines 125 extend horizontally and inwardly toward the access tube 132 for connection into a common oil header 128'.

In order to assemble the bladder 92 and attaching flanges 95-96' and 101'-l02 onto the mandrel 93', most desirably the lower flanges 95'-96 have a narrower outside diameter than upper tubular end 104 so they can be passed downwardly through the upper flanges 101-l02' and fastened with beaded edge 98 clamped therebetween. As in the preferred form, the mandrel assembly is merely suspended in the wing tank, and the tubular extension 190 having O-rings 191 is inserted into the recess 188 beneath the wing tank, the recess being axially aligned with the central opening 90 in the tank, and the extension 190 will establish a secure seal against leakage of the cargo around the external surface of the extension into the wing tank enclosure. As in the first alternate form illustrated in FIGS. 8 to 12, air vent and gas vent lines 138 and 140, respectively, extend into communication with the upper end of each wing tank and lead into header systems in the upper access tubes 126 and 127. The electrical equipment may be distributed through different access tubes.

Accordingly, from the foregoing, it will be appreciated that the alternate forms of invention disclosed herein provide for greatly increased efficiency and dependability in the transportation of liquid cargo, particularly of petroleum products such as oil. In the alternate forms disclosed in FIGS. 8 to 15, an improved cell construction has been devised which will afford greatly increased cargo capacity since the bladders will completely occupy the space within the cells, and through utilization of a mandrel assembly provide for a more effective means of delivery and discharge of the oil. Moreover, as described, the bladders can be readily removed for cleaning purposes merely by disconnecting the mandrel heads and lifting the mandrel assemblies out of their respective wing tanks. When the lift eyes are not in use, blanking plugs are inserted through the central opening 112 down to the point of communication of the oil lines 125 with the center openings; suitable pressure tests may be conducted through the center openings to determine the presence or absence of leaks in the O-ring seals.

When the vessel is completely loaded through the loading circuit as described, the buoyancy of the vessel may be suitably regulated through separate ballast tanks, if additional means of regulating the buoyancy is required. Again however it will be noted that relative amounts of oil supplied to each tank may be varied and this will also serve as an effective means of regulating the buoyancy of the vessel and its surface trim. While the vessel is being unloaded, sea water will fill, or partially fill, each of the wing tanks to occupy the space formerly occupied by the oil cargo with the bladders in collapsed condition against their mandrels and in this way establish the ballast for the return trip.

It is therefore to be understood that various modifications and changes may be resorted to in the preferred and alternate forms described and illustrated herein without departing from the scope of the present invention as defined by the appended claims.

What is claimed is:

1. In a cargo vessel, a plurality of storage cells for liquid cargo arranged in mutually reinforcing relation constituting a structural part of the vessel, each cell comprising an outer rigid enclosure at least partially filled with ballast, an inner expansible container secured within each outer enclosure including means for introducing and removing liquid cargo into and from said container, each said storage cell including means for introducing and removing a gaseous fluid into and from the upper end of each said enclosure and means for admitting and removing sea water into and from the lower end of each said enclosure.

2. In a cargo vessel according to claim 1, said outer rigid enclosure being generally rectangular in crosssection and said inner container being generally circular in cross-section, said container being composed of a reinforced rubber or rubber-like material.

3. In a cargo transport vessel, a storage cell for liquid cargo comprising an outer, vertically extending, rectangular tank at least partially filled with ballast, an inner expansible bladder secured within said tank including means for introducing liquid cargo into said bladder whereby to isolate the cargo from the ballast within said tank, said rectangular tank being closed at opposite upper and lower ends and provided with means for admitting and removing sea water into and from the lower end of said tank and to define the ballast within said tank, and means for admitting and removing a gaseous fluid into and from the upper end of said tank.

4. In a cargo transport vessel according to claim 3, said means for admitting sea water and gaseous fluid into said tank being provided with remote control valves to regulate the sea water and the amount and density of fluid admitted into said tank.

5. In a cargo transport vessel according to claim 3, there being a series of storage cells arranged in abutting, side-by-side relation throughout a substantial portion of said vessel, each said cell including means for regulating the amount of sea water in each of said tanks.

6. A submarine tanker adapted for transportation of petroleum comprising in combination:

a plurality of liquid cargo storage cells arranged in abutting manually reinforcing relation to one another and constituting a structural part of said tanker, each of said storage cells including an outer, vertical disposed tank,

an inner expansible bladder composed of a rubber or rubber-like material anchored within said tank at its lower end and a petroleum inlet connected to the upper end of said bladder for introduction and h a. M

13 removal of petroleum into and from said bladder, the lower end of said tank provided with ports for the introduction and removal of sea water, and means at the upper end of each tank for admitting and removing a gaseous fluid under pressure into and from said tank whereby to cooperate with the sea water in regulating the buoyancy of each said storage cell.

7. A submarine tanker according to claim 6, each of said tanks being generally rectangular in cross-section and each of said bladders being generally circular in cross-section and having longitudinal folds to permit expansion and contraction within each respective tank.

8. In a cargo vessel, a storage cell for liquid cargo.

comprising an outer rigid enclosure, and an inner, flexible expansible container secured within said outer enclosure adjacent to the top and bottom walls of said enclosure including cargo delivery means for introducing and removing liquid cargo into and from said container, said cargo delivery means including a perforated tube extending substantially the length of said container and supporting said container for supply and removal of the cargo into and from said container, said container being capable of expansion to fill the entire space within said enclosure while isolating the cargo from the space within said enclosure.

9. In a cargo vessel according to claim 8, further including means for admitting and removing sea water into and from the lower end of said enclosure.

10. In a cargo vessel according to claim 8, said outer rigid enclosure and said inner container being generally rectangular in cross-section, said container defined by a bladder composed of a reinforced rubber or rubberlike material.

11. In a cargo vessel according to claim 8, said tube including a mandrel head at one end for removable attachment to a structural part of the vessel.

12. In a cargo transport vessel, a storage cell for liquid cargo comprising outer, generally rectangular tanks each defining an air-tight enclosure and having an inner expansible bladder secured to at least two substantially opposite locations within each tank including cargoloading means for introducing liquid cargo into said bladder whereby to isolate the cargo from the ballast within said tank, means for introducing sea water into the lower end of each tank a gas vent communicating with the interior of said bladder and an air vent communicating with the enclosure externally of said bladder; and central cargo storage chambers extending longitudinally in end-to-end relation centrally of said vesel between said outer generally rectangular tanks.

13. In a cargo transport vessel according to claim 12, said means for introducing sea water and cargo being provided with remote control valves to regulate the amount of sea water and amount of cargo introduced into each tank.

14. In a cargo transport vessel according to claim 13, said cargo loading means including a header extending through a passage extending longitudinally of the cargo section of said vessel.

15. A submarine tanker adapted for transportation of crude oil cargo comprising in combination:

a plurality of cargo storage cells arranged in abutting mutually reinforcing relation and uniformly distributed along the port and starboard sides of said tanker, each of said outer storage cells including an outer, generally rectangular pressure-resistant enclosure,

a tubular suspension member provided with a supply and exhaust port removably attached to the upper end of each enclosure and suspended therein,

an inner expansible bladder composed of a rubber or rubber-like material removably secured to upper and lower ends of said tubular member for introduction of cargo therein, the lower end of said enclosure provided with ports for the introduction and removal of sea water, and

at least one central cargo compartment extending longitudinally between said port and starboard cargo tanks including means for introduction and removal of oil cargo into and from said central cargo compartment.

16. A submarine tanker according to claim 15, each of said port and starboard tanks being generally rectangular in cross-section and each of said bladders being generally rectangular in cross-section and capable of expansion to occupy the entire space within said enclosure.

17. A submarine tanker according to claim 15, further including a plurality of storage cells defining outer impact-resistant sides of said tanker.

18. A submarine tanker according to claim 15, gaseous fluid being introduced into the upper end of each cell, the gaseous fluid selected from the group consisting of air and hydrogen peroxide.

19. A submarine tanker according to claim 15, the lower ends of at least selected cells being in open communication with the sea water to define the ballast in said cells, the cargo in each cell being isolated from the cargo in other cells whereby to limit loss in event of collision and to prevent contamination of sea water by the liquid cargo.

20. A cargo transport vessel adapted for transportation of oil cargo comprising in combination:

an outer, pressure-resistant hull;

a plurality of separate cargo storage cells arranged in abutting, mutually reinforcing relation to one another and positioned at least along the port and starboard sides of said vessel, each of said outer storage cells including outer walls composed at least in part of high strength concrete defining a pressure-resistant enclosure and an inner flexible and expansible container therein;

at least one central cargo compartment extending longitudinally between said port and starboard cargo storage cells including means for introduction and removal of oil cargo into and from said central cargo compartment;

common supply and discharge means for selectively supplying and discharging cargo into and from each of said containers for storage therein; and

means for venting gas and air from each cell, and

means for regulating the ballast in said vessel in relation to the load of the oil cargo contained in the vessel.

21. A cargo transport vessel according to claim 20 each of said port and starboard cells being vertically disposed and arranged in honeycomb fashion.

22. A cargo transport vessel according to claim 20, said storage cells defining outer impact-resistant sides of said tanker.

23. A submarine tanker according to claim 22, the lower ends of at least selected cells being in open communication with the sea water to define the ballast in said vessel, the cargo in each cell being isolated from the cargo in other cells whereby to limit loss in the event of collision and to prevent contamination of sea water by the liquid cargo. 

1. In a cargo vessel, a plurality of storage cells for liquid cargo arranged in mutually reinforcing relation constituting a structural part of the vessel, each cell comprising an outer rigid enclosure at least partially filled with ballast, an inner expansible container secured within each outer enclosure including means for introducing and removing liquid cargo into and from said container, each said storage cell including means for introducing and removing a gaseous fluid into and from the upper end of each said enclosure and means for admitting and removing sea water into and from the lower end of each said enclosure.
 2. In a cargo vessel according to claim 1, said outer rigid enclosure being generally rectangular in cross-section and said inner container being generally circular in cross-section, said container being composed of a reinforced rubber or rubber-like material.
 3. In a cargo transport vessel, a storage cell for liquid cargo comprising an outer, vertically extending, rectangular tank at least partially filled with ballast, an inner expansible bladder secured within said tank including means for introducing liquid cargo into said bladder whereby to isolate the cargo from the ballast within said tank, said rectangular tank being closed at opposite upper and lower ends and provided with means for admitting and removing sea water into and from the lower end of said tank and to define the ballast within said tank, and means for admitting and removing a gaseous fluid into and from the upper end of said tank.
 4. In a cargo transport vessel according to claim 3, said means for admitting sea water and gaseous fluid into said tank being provided with remote control valves to regulate the sea water and the amount and density of fluid admitted into said tank.
 5. In a cargo transport vessel according to claim 3, there being a series of storage cells arranged in abutting, side-by-side relation throughout a substantial portion of said vessel, each said cell including means for regulating the amount of sea water in each of said tanks.
 6. A submarine tanker adapted for transportation of petroleum comprising in combination: a plurality of liquid cargo storage cells arranged in abutting manually reinforcing relation to one another and constituting a structural part of said tanker, each of said storage cells including an outer, vertical disposed tank, an inner expansible bladder composed of a rubber or rubber-like material anchored within said tank at its lower end and a petroleum inlet connected to the upper end of said bladder for introduction and removal of petroleum into and from said bladder, the lower end of said tank provided with ports for the introduction and removal of sea water, and means at the upper end of each tank for admitting and removing a gaseous fluid under pressure into and from said tank whereby to cooperate with the sea water in regulating the buoyancy of each said storage cell.
 7. A submarine tanker according to claim 6, each of said tanks being generally rectangular in cross-section and each of said bladders being generally circular in cross-section and having longitudinal folds to permit expansion and contraction within each respective tank.
 8. In a cargo vessel, a storage cell for liquid cargo comprising an outer rigid enclosure, and an inner, flexible expansible container secured within said outer enclosure adjacent to the top and bottom walls of said enclosure including cargo delivery means for introducing and removing liquid cargo into and from said container, said cargo delivery means including a perforated tube extending substantially the length of said container and supporting said container for supply and removal of the cargo into and from said container, said container being capable of expansion to fill the entire space within said enclosure while isolating the cargo from the space within said enclosure.
 9. In a cargo vessel according to claim 8, further including means for admitting and removing sea water into and from the lower end of said enclosure.
 10. In a cargo vessel according to claim 8, said outer rigid enclosure and said inner container being generally rectangular in cross-section, said container defined by a bladder composed of a reinforced rubber or rubber-like material.
 11. In a cargo vessel according to claim 8, said tube including a mandrel head at one end for removable attachment to a structural part of the vessel.
 12. In a cargo transport vessel, a storage cell for liquid cargo comprising outer, generally rectangular tanks each defining an air-tight enclosure and having an inner expansible bladder secured to at least two substantially opposite locations within each tank including cargo-loading means for introducing liquid cargo into said bladder whereby to isolate the cargo from the ballast within said tank, means for introducing sea water into the lower end of each tank a gas vent communicating with the interior of said bladder and an air vent communicating with the enclosure externally of said bladder; and central cargo storage chambers extending longitudinally in end-to-end relation centrally of said vesel between said outer generally rectangular tanks.
 13. In a cargo transport vessel according to claim 12, said means for introducing sea water and cargo being provided with remote control valves to regulate the amount of sea water and amount of cargo introduced into each tank.
 14. In a cargo transport vessel according to claim 13, said cargo loading means including a header extending through a passage extending longitudinally of the cargo section of said vessel.
 15. A submarine tanker adapted for transportation of crude oil cargo comprising in combination: a plurality of cargo storage cells arranged in abutting mutually reinforcing relation and uniformly distributed along the port and starboard sides of said tanker, each of said outer storage cells including an outer, generally rectangular pressure-resistant enclosure, a tubular suspension member provided with a supply and exhaust port removably attached to the upper end of each enclosure and suspended therein, an inner expansible bladder composed of a rubber or rubber-like material removably secured to upper and lower ends of said tubular member for introduction of cargo therein, the lower end of said enclosure provided with ports for the introduction and removal of sea water, and at least one central cargo compartment extending longitudinally between said port and starboard cargo tanks including means for introduction and removal of oil cargo into and from said central cargo compartment.
 16. A submarine tanker according to claim 15, each of said port and starboard tanks being generally rectangular in cross-section and each of said bladders being generally rectangular in cross-section and capable of expansion to occupy the entire space within said enclosure.
 17. A submarine tanker according to claim 15, further including a plurality of storage cells defining outer impact-resistant sides of said tanker.
 18. A submarine tanker according to claim 15, gaseous fluid being introduced into the upper end of each cell, the gaseous fluid selected from the group consisting of air and hydrogen peroxide.
 19. A submarine tanker according to claim 15, the lower ends of at least selected cells being in open communication with the sea water to define the ballast in said cells, the cargo in each cell being isolated from the cargo in other cells whereby to limit loss in event of collision and to prevent contamination of sea water by the liquid cargo.
 20. A cargo transport vessel adapted for transportation of oil cargo comprising in combination: an outer, pressure-resistant hull; a plurality of separate cargo storage cells arranged in abutting, mutually reinforcing relation to one another and positioned at least along the port and starboard sides of said vessel, each of said outer storage cells including outer walls composed at least in part of high strength concrete defining a pressure-resistant enclosure and an inner flexible and expansible container therein; at least one central cargo compartment extending longitudinally between said port and starboard cargo storage cells including means for introduction and removal of oil cargo into and from said central cargo compartment; common supply and discharge means for selectively supplying and discharging cargo into and from each of said containers for storage therein; and means for venting gas and air from each cell, and means for regulating the ballast in said vessel in relation to the load of the oil cargo contained in the vessel.
 21. A cargo transport vessel according to claim 20 each of said port and starboard cells being vertically disposed and arranged in honeycomb fashion.
 22. A cargo transport vessel according to claim 20, said storage cells defining outer impact-resistant sides of said tanker.
 23. A submarine tanker according to claim 22, the lower ends of at least selected cells being in open communication with the sea water to define the ballast in said vessel, the cargo in each cell being isolated from the cargo in other cells whereby to limit loss in the event of collision and to prevent contamination of sea water by the liquid cargo. 